离子液体的定量结构-性质/活性研究

本文系统介绍了离子液体定量结构-性质/活性相关(QSPR/QSAR)的研究方法和步骤,综述了QSPR/QSAR在离子液体的熔点、有机物在离子液体中的无限稀释活度系数、离子液体的表面张力、离子液体的电导率、有机物在离子液体中的溶解度、离子液体的黏度以及离子液体的生物毒性和降解性等方面的最新研究进展,总结了该方法的优缺点,并对未来的研究趋势进行了展望。     

离子液体中有机物溶解度的QSPR模型分析

采用偏最小二乘(PLS)分析方法对84个有机物在四种不同的离子液体中的溶解度进行基于VolSurf参数的定量构性关系(QSPR)研究,取得较好的结果.训练集模型对预测集具有良好的预测能力.参数分析表明有机物具有较大体积的亲水区域,对溶解度有利,且有机物与离子液体之间的相互作用能约为-0.84kJ·mol-1.一定的疏水性对溶解度也是有利因素,当离子液体具有小体积的疏水取代基,有机物具有不对称的局部疏水区域对溶解度有利,当离子液体具有大体积或多个疏水取代基,有机物较高的疏水体积对溶解度有利.多元线性回归(MLR)显示亲水参数W1最重要,表明分子的亲水性是影响有机物在离子液体中溶解的关键因素.     

离子液体作为微波吸收剂促进苯甲醛与巴比妥酸的缩合反应

离子液体是纯粹由离子组成的液体,通常由二烷基季铵阳离子与四氟硼酸根、六氟磷酸根、卤素负离子等阴离子组成.离子液体具有强极性、低蒸汽压,对无机和有机物具有良好的溶解性以及对绝大部分试剂稳定等一系列特殊性质,常作为反应介质或催化剂用于有机合成中[1,2].     

离子液体的QSPR/QSAR研究

离子液体以其独特的性质广受关注,人们对其潜在的应用价值做了大量的研究,但对离子液体特性和结构与性质/活性相关的研究却很少。本文综述了离子液体定量结构-性质/活性相关(QSPR/QSAR)研究的最新进展,重点介绍了QSPR/QSAR的基本原理和离子液体的熔点、有机化合物在离子液体中的无限稀释活度系数、离子液体的界面张力、有机物在离子液体中的溶解系数和分配系数、离子液体的电导率和黏度以及离子液体的毒性等性质与分子结构的定量关系,并对离子液体分子结构与性质/活性的定量相关研究的发展趋势进行了展望。     

离子液体在萃取技术中的应用

萃取是化学领域应用最广泛的一种单元操作。随着对离子液体研究的不断深入,离子液体以其低毒、低挥发以及可设计等特性,作为环境友好溶剂,在苯系有机物、农药残留、天然有机物、氨基酸、蛋白质、DNA以及金属离子等的萃取、检测技术方面的应用取得了一定的进展,如液液萃取、液相微量萃取、分散相液液微量萃取、固相微量萃取以及含水两相萃取等分离技术中不断有关于离子液体应用的报道,有的甚至取得了非常好的研究成果。本文就离子液体在萃取技术方面的应用,综述了近期国内外的研究进展,探讨了当前存在的问题及研究方向,展望了其应用前景。     

离子液体在萃取分离中的应用研究进展

室温离子液体作为一种新型绿色溶剂,具有液程宽、几乎不挥发、溶解能力强及结构可调等独特的物理化学性质,近年来逐渐被人们认识了解,它在各个领域的应用也得到了初步的发展.本文重点概述了离子液体在萃取分离金属离子方面的研究进展,并对离子液体萃取分离有机物和生物分子的研究作了简要介绍.引用文献54篇.     

反相高效液相色谱法测定离子液体及其中的高沸点有机物

建立了反相键合相液相色谱分析离子液体咪唑类离子液体[bmim]PF6[、bmim]BF4、吡啶类离子液体[bupy]BF4的纯度及其中高沸点有机物的方法.以缓冲溶液控制流动相pH值,显著改善了峰形.保留时间定性,外标法定量.     

室温离子液体混合物的相平衡研究进展

室温离子液体混合物的相平衡数据是设计和优化涉及离子液体的化学反应与分离工程的重要基础。本文综述了近年来室温离子液体混合物，特别是室温离子液体＋有机物体系的气－液平衡、液－液平衡和固－液平衡的研究进展，总结了这些混合物相行为的基本热力学规律以及对萃取分离工程的指导作用。     

离子液体处理含油污水实验研究

合成出了适合于含油污水处理的憎水性离子液体,研究了离子液体对含油污水的处理条件。当离子液体与含油污水体积比为1∶5,pH值为5,处理15min后,水中油的去除率为95.6%,COD_Cr的去除率为93.5%,表明应用离子液体可以有效地去除油田采出水中的有机物。同时考察了再生离子液体对除油效果的影响,其五次平行实验的除油率达95.4%,COD_Cr去除率为93.2%,表明离子液体可以回收利用。在此基础上,分析了离子液体对含油污水处理的作用机理。     

新型N-甲基-N-烯丙基吗啡啉季铵盐类离子液体的合成

离子液体对某些无机和有机物溶解性能好、液态温度和电化学窗口范围宽、热稳定性高、易制备,因而近年来成为国内外研究的热点,目前的离子液体大多由烷基吡啶或双烷基咪唑季铵盐阳离子与氯铝酸根、氟硼酸根、六氟磷酸根以及其它大的阴离子构成,在季铵盐类离子液体中,     

Application of ionic liquids as plasticizers for poly(methyl methacrylate)

The room temperature ionic liquid, 1-butyl-3-methylimidazolium hexafluorophosphate, [C4mim][PF6] was found to be an efficient plasticizer for poly(methyl methacrylate), prepared by in situ radical polymerization in the ionic liquid medium; the polymers have physical characteristics comparable with those containing traditional plasticizers and retain greater thermal stability.     

SET‐LRP of acrylonitrile in ionic liquids without any ligand

Use of ionic liquids as reaction media was investigated in the design of an environmentally friendly single electron transfer‐living radical polymerization (SET‐LRP) for acrylonitrile (AN) without any ligand by using Fe(0) wire as catalyst and 2‐bromopropionitrile as initiator. 1‐Methylimidazolium acetate ([mim][AT]), 1‐methylimidazolium propionate ([mim][PT]), and 1‐methylimidazolium valerate ([mim][VT]) were applied in this study. First‐order kinetics of polymerization with respect to the monomer concentration, linear increase of the molecular weight, and narrow polydispersity with monomer conversion showed the controlled/living radical polymerization characters. The sequence of the apparent polymerization rate constant of SET‐LRP of AN was k_app ([mim][AT]) > k_app ([mim][PT]) > k_app ([mim][VT]). The living feature of the polymerization was also confirmed by chain extensions of polyacrylonitrile with methyl methacrylate. All three ionic liquids were recycled and reused and had no obvious effect on the controlled/living nature of SET‐LRP of AN. © 2011 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2011     

Reverse ATRP Process of Methacrylonitrile in [C4mim][PF6]

In this original experiment, an ionic liquid, 1-butyl-3-methylimidazolium hexafluorophosphate ([C₄mim][PF₆]), was used as the reaction media for reverse atom transfer radical polymerization of methacrylonitrile (MAN) initiated by azobisisobutyronitrile (AIBN) with FeCl₃ and isophthalic acid (IA) as catalyst and ligand. The polymerization in [C₄mim][PF₆] proceeded in a well-controlled manner as evidenced by kinetic studies. Compared with the polymerization in N, N-dimethylformamide (DMF), the polymerization in [C₄mim][PF₆] not only showed better control of molecular weight and narrower molecular weight distribution but also provided more rapid reaction rate with the ratio of [MAN]:[AIBN]:[FeCl₃]:[IA] at 300:1:2:4. The block copolymer PMAN-b-PSt was obtained via a conventional ATRP process in [C₄mim][PF₆] by using the resulting PMAN as macroinitiator. [C₄mim][PF₆] and FeCl₃/IA could be easily recycled and reused and had no effect on the living nature of reverse atom transfer radical polymerization of MAN.     

Reverse ATRP process of acrylonitrile in the presence of ionic liquids

An ionic liquid, 1‐butyl‐3‐methylimidazolium tetrafluoroborate ([C₄mim] [BF₄]), was first used as the solvent in azobisisobutyronitrile (AIBN)‐initiated reverse atom transfer radical polymerization (RATRP) of acrylonitrile with FeCl₃/succinic acid (SA) as the catalyst system. The polymerization in [C₄mim][BF₄] proceeded in a well‐controlled manner as evidenced by kinetic studies. Compared with the polymerization in bulk, the polymerization in [C₄mim][BF₄] not only showed the best control of molecular weight and its distribution but also provided rather rapid reaction rate with the ratio of [C₄mim][BF₄] at 200:1:2:4. The polymerization apparent activation energies in [C₄mim][BF₄] and bulk were calculated to be 48.2 and 55.7 kJ mol^?1, respectively. Polyacrylonitrile obtained was successfully used as a macroinitiator to proceed the chain extension polymerization in [C₄mim][BF₄] via a conventional ATRP process. [C₄mim][BF₄] and the catalyst system could be easily recycled and reused after simple purification and had no effect on the living nature of polymerization. © 2008 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 46: 2701–2707, 2008     

Atom transfer radical polymerization of methyl methacrylate by copper(I)‐pyridine‐2‐carboximidate catalysts

Pyridine‐2‐carboximidates [methyl ( 1a ), ethyl ( 1b ), isopropyl ( 1c ), cyclopentyl ( 1d ), cyclohexyl ( 1e ), n‐octyl ( 1f ), and benzyl ( 1g )] were prepared from the reaction of 2‐cyanopyridine with the corresponding alcohols. Cyclopentyl‐substituted 1d was found to be a highly effective ligand for copper‐catalyzed atom transfer radical polymerization (ATRP) of methyl methacrylate (MMA). For example, the observed rate constant for a CuBr/ 1d catalytic system was found to be nearly twice as high as the cyclohexyl‐substituted CuBr/ 1e catalytic system [k_obs = (1.19 vs 0.56) × 10^?4 s^?1). The effects of the solvents, temperature, catalyst/initiator, and solvent/monomer ratio on the ATRP of MMA were studied systematically for the CuBr/ 1d catalytic system. The optimum condition for the ATRP of MMA was found to be a 1:2:1:400 [CuBr]_o/[ 1d ]_o/[ethyl 2‐bromoisobutyrate]_o/[MMA]_o ratio at 60 °C in veratrole solution, which yielded well‐defined poly(MMA) with a narrow molecular weight distribution of 1.14. The catalytically active copper complex 2d was isolated from the reaction of CuBr with 1d . Narrow molecular weight distributions as low as 1.06 were achieved for the CuBr/ 1d catalytic system by employing 10% of the deactivator CuBr₂. © 2004 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 42: 2747–2755, 2004     

Atom transfer radical polymerization of methyl acrylate,methyl methacrylate and styrene in the presence of trolamine as a highly effective promoter

Transition metal-mediated atom transfer radical polymerization(ATRP) is a ‘‘living'/controlled radical polymerization. Recently, there has been widely increasing interest in reducing the high costs of catalyst separation and post-polymerization purification in ATRP. In this work, trolamine was found to significantly enhance the catalytical performance of Cu Br/N,N,N0,N0-tetrakis(2-pyridylmethyl) ethylenediamine(Cu Br/TPEN) and Cu Br/tris[2-(dimethylamino) ethylamine](Cu Br/Me6TREN). With the addition of 25-fold molar amount of trolamine relative to Cu Br, the catalyst loadings of Cu Br/TPEN and Cu Br/Me6 TREN were dramatically reduced from a catalyst-to-initiator ratio of 1 to 0.01 and 0.05,respectively. The polymerizations of methyl acrylate, methyl methacrylate and styrene still showed first-order kinetics in the presence of trolamine and produced poly(methyl acrylate), poly(methyl methacrylate) and polystyrene with molecular weights close to theoretical values and low polydispersities. These results indicate that trolamine is a highly effective and versatile promoter for ATRP and is promising for potential industrial application.     

Kinetic study of the oxidative addition of methyl iodide to Vaska’s complex in ionic liquids

Oxidative addition of methyl iodide to Vaska’s complex in the ionic liquids 1-butyl-3-methylimidazolium triflate [C₄mim][OTf], [C₄mim] bis(trifluormethylsulfonyl)imide [Tf₂N], and N-hexylpyridinium [C₆pyr][Tf₂N] occurred cleanly to give the expected Ir(III) oxidative addition product. Pseudo-first order rate constants were determined for the oxidative addition reaction in each solvent ([Vaska’s] = 0.25 mM, [CH₃I] = 37.5 mM). The observed rate constants under these conditions were 5-10 times slower than the rate seen in DMF. At high methyl iodide concentrations (>23 mM), the expected first order dependence on methyl iodide was not observed. In each ionic liquid, there was no change in the reaction rates within experimental error over the methyl iodide concentration range of 23-75 mM. At lower methyl iodide concentration, a decrease in rate was observed in [C₄mim][Tf₂N] with decreasing concentration of methyl iodide.     

ARGET ATRP of acrylonitrile with ionic liquid as reaction media and 1,1,4,7,7‐pentamethyldiethylenetriamine as both ligand and reducing agent in the presence of air

[C₁₂mim][BF₄], [C₈mim][BF₄], and [C₄mim][BF₄] were first applied as reaction media for atom transfer radical polymerization using activators regenerated by electron transfer (ARGET ATRP) of acrylonitrile (AN) with 1,1,4,7,7‐pentamethyldiethylenetriamine (PMDETA) as both ligand and reducing agent in the presence of air. The rate of polymerization in [C₁₂mim][BF₄] was considerably faster than in [C₈mim][BF₄] and [C₄mim][BF₄]. ARGET ATRP of AN in [C₁₂mim][BF₄] were better controlled than in [C₈mim][BF₄] and [C₄mim][BF₄] under the same experimental conditions. With an increase in the content of PMDETA, the polymerization provided an accelerated reaction rate and a broader polymer molecular weight distribution. A slow polymerization rate and a broad polydispersity index were observed using TMEDA instead of PMDETA as both ligand and reducing agent. There was an obvious induction period with CuCl₂ instead of CuBr₂ as catalyst. Well‐defined PAN‐b‐PMMA with higher molecular weight at 104,560 and relatively broader distribution at 1.35 was successfully prepared with PAN as macroinitiator via ARGET ATRP in [C₁₂mim][BF₄] in the presence of air. The resultant fibers were obtained with the fineness at 1.17dtex and the tenacity at 6.03cN · dtex^?1. Copyright © 2010 John Wiley & Sons, Ltd.     

Closer to the "ideal recoverable catalyst" for atom transfer radical polymerization using a molecular non-fluorous thermomorphic system

The tetramine ligand 1 hexasubstituted by very long alkyl chains (C18H37) exhibits an exceptionally large temperature-dependent solubility in 1,4-dioxane, its solubility increasing ca. approximately 104-fold between 23 and 50 degrees C. The preformed copper(I) complex CuBr/1 was shown to catalyze the atom transfer radical polymerization of methyl methacrylate with good control of the molar masses and polydispersities. Due to the thermoresponsive character of CuBr/1 polymerizations were carried out in homogeneous conditions while lowering the temperature to 10 degrees C led to the precipitation of the catalyst. Catalyst recovery was achieved with high yield ( approximately 95%) by a simple filtration under noninert atmosphere. Very low residual copper contamination ( approximately 200 ppm) was measured in the final polymer. The catalyst was recycled two times without significant loss of activity.     

Functionalized random copolymers from versatile one‐pot click chemistry/ATRP tandems approaches

Two complementary tandem strategies based on the one‐pot combination of click chemistry and atom transfer radical polymerization (ATRP) are studied. Initially, functionalized random copolymers are obtained by copolymerization of methyl methacrylate and propargyl methacrylate simultaneously to the click chemistry coupling of a monofunctional azide. Then, an approach based on the copolymerization of methyl methacrylate and 11‐azido‐undecanoyl methacrylate simultaneously to the click chemistry coupling of a monofunctional alkyne is also investigated. For both the approach, polymerization and click chemistry coupling are catalyzed by CuBr and bipyridine (Bipy) in diphenylether at 90 °C. The [Bipy]/[CuBr] ratio is varied from 2 to 25 and the ratio of functionalized comonomer from 20 to 70 mol %. Both the tandem strategies proceed with good yields (50–80%) and allow a good control over the characteristics of the resulting random copolymers and macromolecular brushes (M_n ～ 15,000–40,000 g/mol and PDI ～ 1.3–2.0) as well as quantitative click functionalization as characterized by ¹H NMR and size exclusion chromatography analyses. Although the click process is generally completed at the early stage of the process, the rate of polymerization depends on the amount of bipyridine involved. It was found that extending most of the polymerization process out of the click reaction regime results in a better control of the polymerization, preventing the significant occurrence of side reactions. © 2009 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 47: 3803–3813, 2009